Targeted inhibition of the HNF1A/SHH axis by triptolide overcomes paclitaxel resistance in non-small cell lung cancer

Paclitaxel resistance is associated with a poor prognosis in non-small cell lung cancer (NSCLC) patients, and currently, there is no promising drug for paclitaxel resistance. In this study, we investigated the molecular mechanisms underlying the chemoresistance in human NSCLC-derived cell lines. We constructed paclitaxel-resistant NSCLC cell lines (A549/PR and H460/PR) by long-term exposure to paclitaxel. We found that triptolide, a diterpenoid epoxide isolated from the Chinese medicinal herb Tripterygium wilfordii Hook F, effectively enhanced the sensitivity of paclitaxel-resistant cells to paclitaxel by reducing ABCB1 expression in vivo and in vitro. Through high-throughput sequencing, we identified the SHH-initiated Hedgehog signaling pathway playing an important role in this process. We demonstrated that triptolide directly bound to HNF1A, one of the transcription factors of SHH, and inhibited HNF1A/SHH expression, ensuing in attenuation of Hedgehog signaling. In NSCLC tumor tissue microarrays and cancer network databases, we found a positive correlation between HNF1A and SHH expression. Our results illuminate a novel molecular mechanism through which triptolide targets and inhibits HNF1A, thereby impeding the activation of the Hedgehog signaling pathway and reducing the expression of ABCB1. This study suggests the potential clinical application of triptolide and provides promising prospects in targeting the HNF1A/SHH pathway as a therapeutic strategy for NSCLC patients with paclitaxel resistance. Schematic diagram showing that triptolide overcomes paclitaxel resistance by mediating inhibition of the HNF1A/SHH/ABCB1 axis.

[Study on the mechanism of cross-linked hyaluronic acid-dexamethasone hydrogelin post-traumatic osteoarthritis]

Objective: To explore the mechanism of cross-linked hyaluronic acid-dexamethasone hydrogel (cHA-Dex) in inhibiting chondrocyte apoptosis and alleviating early post-traumatic osteoarthritis (PTOA). Methods: To generate PTOA model, anterior cruciate ligament transection (ACLT)was performed on SD rats (n=70), and the sham surgery group (n=70) was set as control. The changes in inflammatory indicators such as interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-3 (MMP-3), and matrix metalloproteinase-13 (MMP-13) in the joint lavage fluid were measured at different time points (1-14 days, 5 rats at each time point) after surgery. The cHA-Dex (0.5 mg/ml) hydrogel (experimental group, n=70) and ordinary low-molecular-weight hyaluronic acid (HA) hydrogel premixed with Dex, that was, HA-Dex (0.5 mg/ml) hydrogel (control group, n=70) were injected into the joint cavity of PTOA rats, and the release amount and cumulative release amount of Dex in the joint fluid of rats at each time point(1-14 days, 5 rats at each time point) were detected to reveal the release mechanism of cHA-Dex hydrogel. The cartilage of knee joint of patients with osteoarthritis (OA) who underwent knee arthroplasty in the Second Hospital of Shanxi Medical University from January 2020 to December 2022 was taken for in vitro tissue block culture (Outbridge score=1 or 2,n=18). After the cartilage tissue block was treated with cHA-Dex hydrogel premixed with 0.1, 0.2, and 0.5 mg/ml Dex, the mRNA expression levels of IL-1β, IL-6, TNF-α, MMP-3, and MMP-13 in the articular cartilage tissue block were detected. OA chondrocytes were isolated from cartilage samples using enzymatic hydrolysis and cultured in vitro (n=18). Chondrocytes were divided into 4 groups: saline, cHA hydrogel, Dex (0.5 mg/ml), and cHA-Dex (0.5 mg/ml) hydrogel group. The effects of different interventions on chondrocyte proliferation and apoptosis were tested. Results: The Osteoarthritis Research Society International (OARSI) score of safranine O-solid green staining in PTOA group was 3.34±0.35, and it was 1.17±0.21 in Sham group(P=0.010). The Meachim score of knee joint osteophytes in PTOA rats was significantly higher than that in the Sham group (2.66±0.41 vs 0.22±0.17, P=0.010), indicating PTOA model in rat was established successfully. The cHA-Dex hydrogel, which corresponded to the peak changes of inflammatory factors in the joints of PTOA rats in the early stage, was also released in the early stage and sustained-released in the late stage. After the OA articular cartilage tissue block was treated with cHA-Dex hydrogel premixed with 0.1, 0.2, and 0.5 mg/ml Dex, the mRNA expression levels of IL-1 β, IL-6, TNF-α, MMP-3, and MMP-13 in the tissue block were reduced significantly (all P<0.05) and in a dose-dependent manner. Compared with Dex (0.5 mg/ml) alone group, the apoptosis rate of cHA-Dex (0.5 mg/ml) hydrogel group was significantly reduced (0.60±0.07 vs 6.63±0.98, P=0.010).Compared with the normal saline or the cHA hydrogel alone group, the cHA-Dex (0.5 mg/ml) hydrogel group had significant cell proliferation, and the difference at each time point were all significant statistically (all P<0.05). Conclusion: For the early inflammation of PTOA, cHA-Dex hydrogel can not only inhibit cartilage inflammation, but also reverse the increased apoptosis and decreased proliferation rate of chondrocytes caused by Dex, and finally alleviate the progress of PTOA by releasing Dex.

[Effects of free gracilis muscle flap combined with sural nerve transfer for reconstruction of digital flexion and sensory function of hand in patient with wrist electric burn]

Objective: To explore the effects of free gracilis muscle flap combined with sural nerve transfer for reconstruction of digital flexion and sensory function of hand in patient with severe wrist electric burn. Methods: A retrospective observational study was conducted. From January 2017 to December 2020, 4 patients with wrist high-voltage electric burn admitted to the Department of Burns of the First People's Hospital of Zhengzhou and 4 patients with wrist high-voltage electric burn admitted to the Department of Hand Surgery of Beijing Jishuitan Hospital met the inclusion criteria, including 6 males and 2 females, aged 12 to 52 years. They were all classified as type Ⅱ wrist high-voltage electric burns with median nerve defect. In the first stage, the wounds were repaired with free anterolateral thigh femoral myocutaneous flap. In the second stage, the free gracilis muscle flap combined with sural nerve transplantation was used to reconstruct the digital flexion and sensory function of the affected hand in 3 to 6 months after wound healing. The cut lengths of muscle flap and nerve were 32 to 38 and 28 to 36 cm, respectively. The muscle flap donor area and nerve donor area were both closed and sutured. The survival condition of gracilis muscle flap and sural nerve, the wound healing time of recipient area on forearm, the healing time of suture in muscle flap donor area and nerve donor area were observed and recorded after operation, and the recovery of donor and recipient areas was followed up. In 2 years after operation, the muscle strength of thumb and digital flexion and finger sensory function after the hand function reconstruction were evaluated with the evaluation criteria of the hand tendon and nerve repair in the trial standard for the evaluation of functions of upper limbs of Hand Surgery Society of Chinese Medical Association. Results: All the gracilis muscle flap and sural nerve survived successfully after operation. The wound healing time of recipient area on forearm was 10 to 14 days after operation, and the healing time of suture in muscle flap donor area and nerve donor area was 12 to 15 days after operation. The donor and recipient areas recovered well. In the follow-up of 2 years after operation, the muscle strength of thumb and digital flexion was evaluated as follows: 4 cases of grade 5, 3 cases of grade 4, and 1 case of grade 2; the finger sensory function was evaluated as follows: 4 cases of grade S3+, 2 cases of grade S3, and 2 cases of grade S2. Conclusions: For patients with hand dysfunction caused by severe wrist electric burn, free gracilis muscle flap combined with sural nerve transplantation can be used to reconstruct the digital flexion and sensory function of the affected hand. It is a good repair method, which does not cause great damage to thigh muscle flap donor area or calf nerve donor area.

[Clinical effects of partially de-epithelized local flaps in repairing tubercular chest wall defects]

Objective: To explore the clinical effects of partially de-epithelized local flaps in repairing tubercular chest wall defects. Methods: A retrospective observational study was conducted. From April 2010 to February 2021, twelve patients who met the inclusion criteria were admitted to the Department of Burns and Plastic Surgery of the Eighth Medical Center of PLA General Hospital, including 9 males and 3 females with age of (42±18) years. The sizes of tubercular chest wall defects of patients were ranged from 4 cm×3 cm×2 cm to 16 cm×8 cm×5 cm, which were all repaired with partial de-epithelized local flaps. The widths of flaps were equal to the widths of the defects, and the lengths of flaps were 2 cm longer than those of the defects. In one patient, the local flap was too large to close the donor site directly by suturing, so an autologous back free medium thickness skin graft was used for repair. In other patients, the collection areas of local flaps were small, and the donor areas of flaps were directly closed. The duration of operation, intraoperative bleeding, and postoperative drainage volume and indwelling time of drainage tube were observed and recorded. In two weeks after operation, the survival, color, and texture of flaps, the presence of subcutaneous hydrops and skin ulcer, and donor site healing including wound disruption, local infection, hematoma were observed. Chest X-ray, CT scan, or nuclear magnetic resonance imaging was performed in one month after operation to check whether new local hydrops and bone destruction occurred in the chest wall defects and the concomitant tuberculose focus of patients. All patients were followed up for more than 6 months to record whether the surgical incisions of the chest wall defects of the patients were complicated by hypertrophic scar, redness, swelling, and sinus. Results: In surgery, the patient had (104±18) min of operation duration, (119±53) mL of intraoperative bleeding, (134±49) mL of cumulative drainage of drainage tube, and (5.3±1.7) days of drainage tube indwelling time. In two weeks after operation, all the grafted local flaps survived, and the color and texture of flaps were similar to the surrounding normal skin. One patient had fluid leakage from the incision of chest wall defect area with the incision partially dehisced, which healed well after a phase Ⅱ operation; no wound infection, subcutaneous hydrops, or wound rupture occurred in other patients. The incisions of donor sites in all the patients healed well and no wound disruption, local infection, or hematoma occurred. One month after operation, no new bone destruction was observed in the operative region by chest imaging examination. Patients were followed up for 6 to 96 months, with one patient having wound swelling, ulceration, and sinus in the operative area of the chest wall defect in 12 months after surgery, which healed after phase Ⅱ operation; the incisions of chest wall defect wounds in other patients healed well and had no scar, redness and swelling, or sinus. Conclusions: Partially de-epithelized local flap could be used in repairing tubercular chest wall defect wounds, with the advantages of flexible flap design, minimal donor site injury, and good postoperative wound healing.

[Clinical application of enlarging greater ischiatic notch by ilium osteotomy to expose the sacral plexus via the gluteal approach]

Objectives: To observe the possibility of enlarging the greater sciatic notch by illium osteotomy through the posterior gluteal approach for reaching the intrapelvic upper sacral plexus as well as the covergence level of sacral plexus,and performing the nerve graft for surgical repairing the sacral plexus ruptured injuries or sacral plexus nerve tumor resection. Methods: The clinical data of 10 patients with sacral plexus injury or sacral plexus nerve tumor underwent the surgical operation via the expanded greater sciatic notch at Department of Hand Surgery,Beijing Jishuitan Hospital from July 2016 to November 2020 were retrospectively analyzed.There were 4 male and 6 female patients,with an age of (38.0±9.3)years (range:26 to 56 years).There were 8 cases with sacral plexus injury at the intrapelvic or covergence level (deep to the piriformis). Out of this 8 cases,4 cases with intrapelvic pan-sacral plexus injury,1 case with upper sacral plexus injury and 3 cases with convergence level pan sacral plexus injury.Another 2 cases were sacral plexus neoplasm.The average time from injury or onset to operation was 10.4 months (range:1.5 to 60.0 months). All cases were performed surgery for reaching the intrapelvic upper sacral plexus as well as the covergence level of sacral plexus with enlarging the greater sciatic notch by illium osteotomy through the posterior gluteal approach.Intraoperation the sacral plexus ruptured injurie was repaired and the sacral plexus nerve tumor was resected.Intraoperative findings,postoperative complications and healing of patients were recorded. Results: All the 10 patients underwent the sacral plexus surgical exploration and cutaneous nerve graft for sacral plexus nerve repairing or neurolysis or neoplasm resection through the posterior gluteal approach successfully.The length and width of illium osteotomy mass were (2.9±0.4)cm (range:2.5 to 3.8 cm) and (2.5±0.5)cm (range:1.5 to 3.4 cm) respectively.The median intraoperative bleeding volume was (M(QR))800(800)ml (range:400 to 2 000 ml).There were no complication with major vascular injury and hematoma formation,and all incisions healed.The postoperative follow-up was 29.8 months (range:1.5 to 54.0 months).Nine cases of iliac osteotomy were healed,and 1 case was not healed because the follow-up was only 1.5 months. Conclusions: The intrapelvic upper sacral plexus and the convergence level of sacral plexus deep to the piriformis can be exposed clearly through this posterior gluteal approach via illium osteotomy for enlarging the greater sciatic notch,and there was enough operative space that surgical exploration and nerve graft or nerve transfer or neoplasm resection can be performed.

Comparison of primary arthrodesis versus open reduction with internal fixation for Lisfranc injuries: Systematic review and meta-analysis

Objective

Multiple studies have compared primary arthrodesis versus open reduction with internal fixation (ORIF) for surgical treatment of fractures of the Lisfranc joint, but their results have been inconsistent. Therefore, the present systematic review and meta-analysis was performed to compare the clinical efficacy of arthrodesis versus ORIF for the treatment of Lisfranc injuries.

Methods

Through searching the Embase, PubMed, PMC, CINAHL, PQDT, and Cochrane Library databases (from July 1998 to July 2018), we identified five case-controlled trials and two randomized controlled trials that compared the clinical efficacy of primary arthrodesis and ORIF for treating Lisfranc injuries. The extracted data were analyzed using Review manager 5.3 software.

Results

Through comparisons of data for primary arthrodesis and ORIF groups, we found no significant differences in the anatomic reduction rate, revision surgery rate, and total rate of complications between the different treatment approaches. However, arthrodesis was associated with a significantly better American Orthopedic Foot and Ankle Society (AOFAS) score, return to duty rate, and visual analog scale score with a lower incidence of hardware removal compared with ORIF.

Conclusions

For the treatment for Lisfranc injuries, primary arthrodesis was superior to ORIF based on a higher AOFAS score, better return to duty rate, lower postoperative pain, and lower requirement for internal fixation removal. Further evidence from future randomized controlled trials with higher quality and larger sample sizes is needed to confirm these findings.

[Effect of primary cilia on growth plate chondrocyte proliferation of young rats with chronic renal insufficiency]

Objective: To observe the effect of primary cilia on growth plate chondrocyte proliferation of young rats with chronic renal insufficiency (CRI). Methods: Male 2-week-old Sprague-Dawley rats were randomly divided into two groups (with 10 in each group): Sham group (only left ureter was exposed) and CRI group (left ureter was ligated). Rats were sacrificed 2 weeks after operation and the total length of tibia was measured. Histological sections of tibia were taken to observe the chondrocytes of growth plate proliferative region and the expression rate of primary cilia. Chondrocytes from growth plate in two groups were isolated and cultured in vitro to P3 generation and the chondrocyte proliferation rate at 24 h were detected. The primary cilia expression rate and cilia length of chondrocytes were measured. Western blot was used to detect the expression of intraflagellar transport 88 (IFT88) protein and the gray scale was analyzed. Results: The total length of tibia was shorter in CRI group [(35.84±4.56) mm vs (42.33±3.44) mm, P=0.002]. The results of tibial histological section showed that chondrocytes of growth plate proliferative region were unorganized and the number of chondrocyte with columnar structure was less in CRI group (2.71±1.10 vs 7.68±1.32, P<0.001). The primary cilia expression rate of chondrocytes was higher in CRI group [(35.53±7.41)% vs (18.31±5.12)%, P<0.001]. The chondrocyte proliferation rate at 24 h was lower in CRI group [(11.38±6.10)% vs (24.35±8.46)%, P=0.001]. The primary cilia expression rate of chondrocytes was higher in CRI group [(60.12±7.86)% vs (32.17±8.97)%, P<0.001], and the primary cilia length of chondrocytes was longer in CRI group [(3.54±1.61) μm vs (1.96±0.82) μm, P=0.012]. The protein IFT88 was more highly expressed in CRI group (0.47±0.23 vs 0.17±0.10, P=0.001). Conclusion: The primary cilia expression rate of growth plate chondrocytes was higher in the rats with CRI, resulting in decreased chondrocyte proliferation rate and growth retardation of tibial growth plate.

Blood flow index as an indicator of successful sciatic nerve block: a prospective observational study using laser speckle contrast imaging

BACKGROUND

Laser speckle contrast imaging allows real-time, non-invasive, quantitative measurements of regional blood flow. The objectives of this prospective observational study were to use laser speckle contrast imaging to evaluate blood flow changes after sciatic nerve block, and to determine whether this novel optical technique can evaluate block success.

METHODS

This observational study included 63 adult patients undergoing elective lower limb surgery with sciatic nerve block. Blood flow images and blood flow index (BFI) values of toes were recorded using laser speckle contrast imaging 5 min before nerve block and at 5 min intervals until 30 min after sciatic block. The sensitivity, specificity, and cut-off value of laser speckle contrast imaging for predicting successful sciatic block were determined by receiver operator characteristic (ROC) curve analysis.

RESULTS

The BFI values of toes were significantly increased at each time point after successful sciatic block, compared with the baseline value obtained 5 min before nerve block; in failed sciatic block, there were no significant differences. For successful sciatic block, the highest increase of BFI value was at the big toe. BFI increase of the big toe at 10 min after sciatic block has great potential as an indicator of block success. The area under the ROC curve was 0.954 at a cut-off value of 8.48 perfusion units (PU) with a sensitivity of 89% and a specificity of 100%.

CONCLUSIONS

Laser speckle contrast imaging might be an early, objective, quantitative, and reliable indicator of successful sciatic block. BFI increase of the big toe not reaching 8.48 PU within 10 min after sciatic block indicates block failure.

CLINICAL TRIAL REGISTRATION

NCT03169517.

[Application of a microvascular anastomotic coupling device in solitary upper extremity artery injury repairs]

OBJECTIVE

To investigate the outcomes of applying microvascular anastomotic coupling devices in solitary upper extremity artery injury repairs and to optimize parameters for optimal clinical outcome.

METHODS

From March to September 2013, 19 injured arteries from 18 male patients who presented at Department of Hand Surgery, Beijing Jishuitan Hospital with traumatic arterial lacerations of their upper extremities went through rapid repair procedures. COUPLER, a microvascular anastomotic coupling device was applied in these artery injury repair operations. The 19 repaired arteries included 3 brachial arteries, 6 ulnar arteries and 10 radial arteries. After the procedures, all the 18 patients were then followed up by clinical specialists and examined with color doppler flow imaging for the effective recovery of artery circulation and upper extremities functionality.

RESULTS

The average time of artery repairs for all the 19 damaged arteries among the 18 patients was 278 s and the average follow-up time was (71.5±40.9) d with the longest follow-up time as 116 d and shortest as 14 d. No patient returned to the operating room after the procedures and after being dismissed from the hospital. None of the 18 cases were reported to have problems with circulation and thrombosis formation in their upper extremities. Color Doppler imaging showed that the arterial anastomotic site for all the 19 repaired arteries were unobstructed with artery blood spectrum at both ends. Three patients with radial artery repairs complained about mild pressure pain at the site of vascular anastomosis; while the other 15 patients all expressed satisfactory outcomes of the surgery and recovery. These evidences indicated that the outcomes of our initial evaluation for the solitary upper extremity artery injury repairs by using anastomotic coupling devices were positive.

CONCLUSION

Our observations have showed that microvascular anastomotic coupling devices can be used for repairing of solitary upper extremity artery injures. The procedures are quick, effective and safe. The clinical application of this microvascular anastomotic coupling device in artery injures is promising, however, additional evidences through further clinical investigation with more cases are warranted.

Industrial wideband noise reduction for hearing aids using a headset with adaptive-feedback active noise cancellation

High-intensity noises are a health hazard for industrial workers, and hearing protection is necessary to prevent hearing loss. Passive methods, such as ear muffs, are ineffective against low-frequency noise. Moreover, many hearing-impaired workers must wear hearing aids to enable communication at their workplace, and such aids can amplify ambient noise. To overcome this problem, the present study developed a headset equipped with a digital signal processing system to implement adaptive-feedback active noise cancellation (AFANC) to reduce low-frequency noise. The proposed AFANC headset was effective against wideband industrial noise, with a maximum noise spectrum power reduction of 30 dB. Furthermore, when used with a hearing aid, it improved the speech signal-to-noise ratio by up to 14 dB. These results suggest that a headset with AFANC would be useful for hearing protection in workplaces with high levels of low-frequency industrial noise, especially for hearing-impaired workers.

Optoacoustic imaging with synthetic aperture focusing and coherence weighting

Optoacoustic imaging takes advantage of high optical contrast and low acoustic scattering and has found several biomedical applications. In the common backward mode a laser beam illuminates the image object, and an acoustic transducer located on the same side as the laser beam detects the optoacoustic signal produced by thermoelastic effects. A cross-sectional image is formed by laterally scanning the laser beam and the transducer. Although the laser beam width is generally narrow to provide good lateral resolution, strong optical scattering in tissue broadens the optical illumination pattern and thus degrades the lateral resolution. To solve this problem, a combination of the synthetic aperture focusing technique with coherence weighting is proposed. This method synthesizes a large aperture by summing properly delayed signals received at different positions. The focusing quality is further improved by using the signal coherence as an image quality index. A phantom comprising hair threads in a 1% milk solution was imaged with an optoacoustic imaging system. The results show that the proposed technique improved lateral resolution by 400-800% and the signal-to-noise ratio by 7-23 dB over conventional techniques.

Left ventricular cavity-to-myocardium count ratio in exercise and resting technetium-99m-tetrofosmin SPECT: correlation with left ventricular function

The aim of this study was to assess the value of the cavity-to-myocardium count ratio (C/M ratio) calculated in exercise and resting technetium-99m (Tc-99m) tetrofosmin single photon emission computed tomography (SPECT) images to identify patients with depressed exercise and resting left ventricular ejection fraction (LVEF). We studied 60 patients with recent coronary artery diseases (CAD) undergoing first-pass ventriculography to calculate LVEF and myocardial perfusion SPECT imaging to calculate left ventricular C/M ratios. The group A of 30 CAD patients with higher LVEF (> or = 40%) had significant higher C/M ratios than the group B of 30 CAD patients with abnormal LVEF (< 40%) during exercise and rest. However, C/M ratios between exercise and rest did not differ significantly in the both groups A and B. There is significant correlation between exercise/rest LVEF and exercise/rest C/M ratios. Tc-99m tetrofosmin C/M ratios calculated SPECT perfusion images are useful parameters in identifying patients with depressed LVEF in CAD patients.

Universal antenatal human immunodeficiency virus testing in Hong Kong: consensus statement

Following the recommendations of the Advisory Council on AIDS, Hong Kong, the Hospital Authority announced plans to introduce universal antenatal screening for human immunodeficiency virus infection and hence, a consensus conference was held to discuss strategies for implementing such screening in Hong Kong. This paper reports the discussions of the consensus conference. The consensus meeting group consisted of 15 clinicians and scientists from Hong Kong, Macau, and Thailand. Seven commonly asked questions concerning mother-to-child transmission of human immunodeficiency virus were selected for discussion by the participating panellists. Information on the laboratory diagnosis of human immunodeficiency virus infection and the efficacy of preventive measures in reducing mother-to-child transmission of human immunodeficiency virus were reviewed. Data from local studies was also presented and discussed. The timing, potential problems, and cost issues involved in testing all pregnant women in Hong Kong for human immunodeficiency virus were then considered.

Tissue harmonic image analysis based on spatial covariance

The van Cittert-Zernike theorem has been widely used to describe spatial covariance of the pressure field backscattered from a speckle object. Spatial covariance contains important information in the context of correlation-based correction of sound velocity inhomogeneities. Previous work was primarily based on spatial covariance analysis for linear imaging. In this paper, we extend the analysis to tissue harmonic imaging. Specifically, we investigate effects of the signal-to-noise ratio (SNR) and sound velocity inhomogeneities on spatial covariance. Results from tissue harmonic imaging are also compared with those from linear imaging. Both simulations and experiments are performed. At high SNRs, although both linear imaging and tissue harmonic imaging have spatial covariance functions close to theory, the spatial covariance of tissue harmonic imaging is consistently lower than that of linear imaging regardless of the presence of sound velocity inhomogeneities. At low SNRs, on the other hand, spatial covariance of tissue harmonic imaging is significantly affected. Because the tissue harmonic signal is much weaker than the linear counterpart, the low SNR reduces the accuracy of correlation-based estimation. It is concluded that the linear signal is more suitable for correlation-based correction of sound velocity inhomogeneities, despite the fact that tissue harmonic imaging generally has improved image quality over linear imaging.

Strain compounding: spatial resolution and performance on human images

Compounding has long been used to reduce speckle brightness variations by incoherently combining partially correlated measurements of the same image object. Conventionally, decorrelation between measurements is introduced by imaging from different spatial positions (i.e., spatial compounding) or within different frequency ranges (i.e., frequency compounding). An alternative compounding approach based on speckle decorrelation of an object under different strain conditions was recently proposed. The new approach was referred to as strain compounding. Speckle correlation of strain compounding was previously analyzed using simulations and radiofrequency (RF) data from a gelatin-based phantom. Results indicated that effective speckle reduction is possible at strains potentially achievable in certain clinical situations. In this paper, performance of strain compounding is further analyzed. Potential degradation in spatial resolution of strain compounding is compared to that of conventional approaches using computer simulations. Results show that strain compounding potentially can achieve the same level of speckle reduction, with less degradation in spatial resolution if a large compression can be applied. Performance of strain compounding is also tested using postdetection human images acquired by a commercial imaging system. Two-dimensional (2-D) speckle tracking is performed to correct for tissue motion resulting from external compression and to ensure that the images to be compounded are spatially matched. Thyroid images show that speckle brightness variations can be effectively reduced without significant degradation in spatial resolution. Speckle reduction in liver imaging is also demonstrated. However, speckle reduction is not as significant as in thyroid imaging, due to the fact that a large compression cannot be achieved.

Elastic properties of tendon measured by two different approaches

Elastic properties of tendon were assessed by two different approaches. Six fresh bovine Achilles tendon specimens were used. The first approach directly measured Young's modulus along the transverse direction (E(perpendicular)) and the longitudinal direction (E(parallel)), using a cyclic compression-relaxation method. Young's moduli were derived based on the measured strain and stress values. The ratio of E(parallel): E(perpendicular) at smaller strains was around 4 and decreased to 0.6 approximately 1.1 at larger strains. The second approach assumed that tendons are transversely isotropic. Three observable second-order elastic stiffness constants (c(11), c(13) and c(33)) were obtained by sound speed measurements along various propagation directions. The measured elastic stiffness constants were also correlated with results from the first approach. It was shown that the transverse isotropy assumption was valid at small strains. However, a significant discrepancy existed between the two approaches. The discrepancy was primarily due to viscoelasticity associated with the first approach.

A capillary zone electrophoretic method for the study of formation of a covalent conjugate between microcystin LR and protein phosphatase 2A

The study of conjugate formation between microcystin (MCYST)-LR and protein phosphatase (PP) 2A, which was isolated from bovine kidney and mouse brain, was achieved by using a highly efficient capillary zone electrophoretic (CZE) separation method. The MCYST-LR-PP2A conjugate (from bovine kidney) was resolved from its precursor after just 15 min of incubation. Moreover, the migration time, and, hence, the total analysis time, was less than 5 min. While the present findings of the time lag between conjugate formation and full inhibition are not novel, the CZE method does provide an alternative tool to HPLC with a higher separation efficiency to yield data for kinetic and mechanistic studies of the enzyme-toxin interaction. The CZE data reported here were found not to be adequately described by a first-order kinetic model. Moreover, the CZE method, which involves the use of a low ionic strength aqueous buffer, does not suffer from the drawback of the use of denaturing organic solvents such as those used in HPLC.

On velocity estimation using speckle decorrelation

Quantitative estimation of blood velocity using Doppler techniques is fundamentally limited because only the axial component can be detected. Speckle decorrelation resulting from scatterer motion may be used to compute non-axial components and to obtain quantitative flow information. Based on both simulations and experimental results, it is shown that the decorrelation technique is feasible only for constant flows. If flow gradients are present, the correlation between two signals along the same line of observation may be significantly affected by the gradients. Therefore, the decorrelation method cannot be used for quantitative flow estimation if flow gradients are not accurately measured and effects on signal correlation are not fully compensated. Results in this paper show that accurate estimation of flow gradients is practically difficult. It is further shown that effects of signal-to-noise ratio (SNR) on the correlation must also be taken into account for quantitative flow analysis.

Neurophysiological effects of recurrent laryngeal and thoracic vagus nerves on mediating the neurogenic inflammation of the trachea, bronchi, and esophagus of rats

The present study aims to investigate the neurophysiological effects of recurrent laryngeal nerve and thoracic vagus nerve on the non-cholinergic regulation of neurogenic plasma extravasation of the rat trachea, bronchi, and esophagus. Through thoracotomy, three nerve components, the right thoracic vagal trunk, thoracic vagus nerve, and recurrent laryngeal nerve, were identified. The experiment was sequentially conducted in four steps. First, the individual nerve component was electrically stimulated and the induced inflammatory responses, as quantified by the area density of India ink-labelled blood vessels in the trachea, bronchial trees and esophagus, were compared. Second, we assessed the relative importance of medial and lateral side of the right thoracic vagus nerve in inducing the inflammatory responses by alternative stimulation of one side with simultaneous severance of the other side of this nerve. Third, we examined the effects of transection of the lateral half of the right thoracic vagus nerve on the degeneration of axon fibers located at the following three sites: the nerve segment proximal to cutting site, bronchial and esophageal nerve branches. Finally, we directly observed the inflammatory histopathology of the right lower trachea after stimulation of the medial half of the right thoracic vagus nerve with transection of its lateral half. In this study, we found that the right recurrent laryngeal nerve was predominant in mediating the neurogenic inflammatory responses of upper and dorsal portions of trachea, whereas the right thoracic vagus nerve was predominant in mediating those of the right lower ventral wall of trachea, right main bronchus, and right lobar bronchial trees. The axon fibers of the right thoracic vagus nerve responsible for mediating the neurogenic inflammatory responses of the right lower ventral trachea were mainly accumulated in the medial half, whereas those innervating the right main bronchus, right lobar bronchial trees, and lower esophagus were largely in the lateral half of this nerve. Transection of the lateral half of the right thoracic vagus nerve resulted in significant degeneration of myelinated fibers in its bronchial and esophageal nerve branches. Histopathological examination of the right lower trachea after electrical stimulation of the medial half of thoracic vagus nerve demonstrated the silver-stained leaky venules with accumulations of inflammatory cells. We thus concluded that afferent C-fibers to upper and dorsal portions of trachea were mainly from recurrent laryngeal nerve. In contrast, the neurogenic inflammatory responses of the right lower trachea were predominantly mediated by the medial half of the right thoracic vagus nerve, and those of the right main bronchus, bronchial trees and lower esophagus were largely by the lateral half of this nerve.

Harmonic leakage and image quality degradation in tissue harmonic imaging

Image quality degradation caused by harmonic leakage was studied for finite amplitude distortion-based harmonic imaging. Various sources of harmonic leakage, including transmit waveform, signal bandwidth, and system nonlinearity, were investigated using both simulations and hydrophone measurements. Effects of harmonic leakage in the presence of sound velocity inhomogeneities were also considered. Results indicated that sidelobe levels of the harmonic beam pattern were directly affected by harmonic leakage when the harmonic signal was obtained by filtering out the fundamental signal. Because sidelobe levels also increase with the bandwidth of the transmitted signal, a trade-off exists between axial resolution and contrast resolution. It is concluded that accurate control of the frequency content of the waveform prior to propagation is necessary to optimize imaging performance of tissue harmonic imaging. The filtering technique was also compared with the pulse inversion technique. It was shown that the pulse inversion technique effectively suppresses harmonic leakage at the cost of imaging frame rate and potential motion artifacts.

Feasibility study of time-intensity-based blood flow measurements using deconvolution

Ultrasonic contrast agents have been used to enhance the acoustic backscattered intensity of blood and to assist the assessment of blood flow parameters. One example is the time-intensity method based on the indicator-dilution theory. In this case, a mixing chamber model can be employed to describe the concentration of the contrast agent as a function of time. By measuring the time intensities at both the input and output of the blood mixing chamber, blood flow information can be obtained if proper deconvolution techniques are applied. Note that most deconvolution techniques assume a linear and time invariant (LTI) system for the mixing of the contrast agent with blood. In this paper, the hypothesis that a blood mixing chamber is an LTI system was tested. Several aspects were studied. One aspect was the linear relationship between the concentration of the contrast agent and the backscattered intensity. The other aspect was the dependence of the derived time constants on the concentration. The concept of an effective mixing volume was also introduced and evaluated. Finally, the input and the output time constants were measured and compared to theory under the LTI assumption. Extensive experiments were performed. Two in vitro flow models were constructed and two contrast agents were used. Results indicated that the LTI assumption does not hold and quantitative flow estimation is generally not possible. Nonetheless, the indicator-dilution theory can still be applied if only relative measurements of the flow rate are required.

Filter-based synthetic transmit and receive focusing

Most diagnostic ultrasonic imaging systems perform fixed focusing on transmit and dynamic focusing on receive. Such systems suffer from image quality degradation at depths away from the transmit focal zone. Several dynamic transmit focusing techniques have been previously investigated. Among them, a filter-based, retrospective focusing technique was proposed to increase the length of the transmit focal zone. In this paper, the filter-based technique is extended from dynamic receive focusing to fixed receive focusing. It is shown that the filtering technique with fixed receive focusing can achieve an image quality similar to that of dynamic receive focusing with filtering. The performance of the proposed approach is verified using real ultrasound data. It is shown that the proposed approach with fixed receive focusing requires a longer filter than that with dynamic receive focusing. Nonetheless, system complexity is greatly reduced with synthetic transmit and receive focusing because the dynamic receive focusing circuit is no longer needed.

Clinical manifestations of tuberculosis in HIV-infected patients

OBJECTIVE

The purpose of the present study was to evaluate the impact of HIV infection on the clinical presentation of tuberculosis.

METHODOLOGY

We retrospectively studied the impact of HIV infection on the clinical presentation of tuberculosis. A total of 60 consecutive patients co-infected with HIV and tuberculosis were identified.

RESULTS

Majority were male (88.3%) and the most common transmission category was heterosexual contact (80%). Most were in the advanced stage of HIV infection; 93% had CD4 cell count less than 200/mm3. Concerning the site of tuberculosis involvement, 37% had pulmonary involvement alone, 13% had extrapulmonary disease involving one single site, 50% had both pulmonary and extrapulmonary involvement. Fifteen (25%) patients also met the criteria of disseminated tuberculosis, who had a significantly lower mean CD4 cell count than those with pulmonary involvement alone (mean 40 vs 102; P = 0.048). Chest radiographs comprised a wide spectrum of manifestations. A considerable proportion had primary pulmonary tuberculosis pattern (38%) and normal radiographs (8.5%).

CONCLUSIONS

Our patients generally had advanced HIV infection; 93% of those had CD4 lymphocyte count < 200/mm3. Extrapulmonary involvement and disseminated disease were common. Radiographic manifestations of pulmonary tuberculosis were often 'atypical' due to the greater proportion of primary tuberculosis among our patients.

Correlation-based correction of sound velocity inhomogeneities using delta-sigma modulators

Delta-sigma (deltasigma) modulator based beamformers have been proposed for high-quality ultrasonic imaging. Due to the high sampling rate and single bit data width, the cost and complexity of the receive beamformer can be significantly reduced. It was shown that with proper dynamic focusing controls, equivalent image quality could be achieved with an adequate signal-to-quantization noise ratio (SQNR). In this paper, deltasigma modulator based beamformers are used for correlation-based phase aberrations correction of sound velocity inhomogeneities in the body. It is shown that the correction can be efficiently implemented at a performance level similar to that of a conventional radio frequency (rf) beamformer. In addition, more than 6 dB contrast improvement is demonstrated. The different dynamic focusing techniques are also investigated in the context of phase aberration correction. It is shown that the single bit dynamic focusing approach does not affect the overall performance of phase aberration correction.

A dynamic focusing technique for delta-sigma-based beamformers

Beamformation using oversampling delta-sigma (deltasigma) modulators has been proposed for diagnostic ultrasound. Such a beamformer can reduce the size, complexity and cost of an imaging system while providing adequate signal-to-quantization noise ratio (SQNR). High quality images can also be generated if dynamic receive delays are applied correctly. Several dynamic focusing techniques were previously proposed. Generally, an additional bit or extra compensation circuit is required to preserve the power and frequency distribution of the signal. Without preserving the power and frequency distribution, the image background noise is increased. In this paper, an alternative technique is presented. The new technique exploits the symmetry of focusing delays relative to the center of a transducer array. By properly synchronizing the delays and selecting the inserted values, no noise is added to the beam sum signal and the image background level is not increased. Using real ultrasound data, it is shown that the proposed technique provides the same imaging performance as the previous approaches with reduced system complexity by using only a single bit to encode the output of the deltasigma modulator.

Antioxidant activity of phenylethanoid glycosides from Brandisia hancei

Brandisia hancei is a medicinal herb in China. The ethanol extract of this plant and four phenylethanoid glycosides, acteoside (1), 2'-acetylacteoside (2), poliumoside (3) and brandioside (4), isolated from it were shown to have inhibitory effects on free radical-induced hemolysis of red blood cells and free radical scavenging activities in vitro. Brandioside (4) and poliumoside (3) showed stronger antioxidant effect than acteoside (1), 2'-acetylacteoside (2) and trolox.

Successful application of extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation as lifesaving therapy for a patient with amniotic fluid embolism

A woman in labor was noted to have amniotic fluid embolism. Extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation were performed post partum, and the vital signs became stable. The ensuing recovery was uneventful. We conclude that extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation should be considered to save the life of a patient with amniotic fluid embolism and left ventricular failure unresponsive to medical therapy.

Micellar electrokinetic capillary chromatographic separation and fluorescent detection of amino acids derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole

Another method has been developed for the separation of amino acids (1 min derivatization plus 22 min separation) by micellar electrokinetic capillary chromatography (MECC) with laser-induced fluorescence detection. Interestingly enough, such work has never been performed on essential amino acids derivatized by 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). Fifteen L-amino acid standards were labelled with NBD-F at 60 degrees C for 1 min, and separated in a buffer system containing 20 mM borate, 25 mM sodium cholate, 10 mM Brij 35 and 2.5% methanol. Methanol was employed to expand the MECC migration time window; whereas Brij 35 was used to improve the fluorescence intensity of amino acid derivatives. This method also indicates that bile salt is effective for MECC separation of ionic analytes. Surprising though, improvements in resolution, sensitivity and speed for amino acids analysis are obtained in this work, which are not initially apparent in just employing another derivatizing reagent. Under optimal conditions, 15 amino acids were separated in a short 22 min analysis time, the shortest ever reported, and detection limits of nanomolar concentration and attomole mass were obtained. Furthermore, RSDs of migration time and peak height are better than 1% and 1.8%, respectively, again the smallest ever reported in the literature.

Hemodynamic assessment of ischemic stroke with near-infrared spectroscopy

OBJECTIVE

To validate near-infrared cerebral topography (NCT) as a practical tool in tracing the regional hemodynamic changes during normal ischemic stroke model of rat.

METHOD

Middle cerebral artery occlusion (MCAO) and photosensitizer induced intracranial infarction model of rat were established. The geometric shape and infarction area were measured by NCT, functional magnetic resonance imaging (fMRI), and TTC stained anatomical imaging techniques.

RESULT

In photosensitizer induced infarction model, the correlation between anatomical infarct area and NCT image area for infarct focus were r = 0.897 for 24 h group (P < 0.05) and r = 0.906 for 2 months group (P < 0.01), respectively. The correlation between anatomical infarction area and NCT image area for infarct focus were r = 0.820 for normothermia group (P < 0.05) and r = 0.851 for hypothermia group (P < 0.05), respectively. The correlation between fMRI and NCT image area for infarction focus were r = 0.874 for normothermia group (P < 0.05) and r = 0.782 for hypothermia group (P < 0. 05), respectively.

CONCLUSION

Measurement with NCT for infarction focus matched well with fMRI and anatomic sample in rats. NCT technique might be a practical tool for short-term prediction of stroke and the rehabilitation after stroke in real time.

Left prefrontal cortex activation during semantic encoding accessed with functional near infrared imaging

OBJECTIVE

To investigate the left prefrontal lobe activation during semantic and non-semantic encoding tasks with functional near-infrared imaging (fNIRI) technique.

METHOD

22 healthy subjects were assigned semantic encoding and non-semantic encoding tasks. During semantic encoding tasks, subjects were asked to make a meaningful sentence including two unrelated Chinese word pairs, while during non-semantic encoding task they were asked to judge whether the two Chinese word pairs had the same morphological structure or not. Light intensity of two wavelengths (760 nm and 850 nm) diffused through skull and left prefrontal lobe were real-time recorded and used to reconstruct the brain activation image during the experiment.

RESULT

With the fNIRI, significant activations were observed in the left inferior prefrontal cortex (Brodmann' areas 45 and 47) during the two tasks, but the evoked activations were more significant for semantic than non-semantic task. These observations were consistent with the results reported by others with functional megnetic resonance imaging (fMRI) and positron-emission tomography PET.

CONCLUSION

The results suggest that fNIRI provides an important, non-invasive way to map the prefrontal activation during cognitive tasks.

Brain MRI of hippocampal volumetry in patients with refractory temporal lobe epilepsy

OBJECTIVE

To detect for hippocampal sclerosis presurgically in a group of patients with refractory temporal lobe epilepsy.

METHODS

Eighty-four consecutive patients with refractory temporal lobe epilepsy were subjected to brain MRI of hippocampal volumetry. A ratio of smaller to larger hippocampal volume was determined and unilateral hippocampal atrophy (HA) was diagnosed if the ratio is less than 0.91.

RESULTS

Unilateral HA was diagnosed in 42 patients (50%) and bilateral HA in 1 patient. Other MRI abnormalities were detected in 18 patients with or without coexisting HA.

CONCLUSIONS

Hippocampal sclerosis can be detected presurgically in many patients by brain MRI. Additional abnormalities not detected by brain CT can also be demonstrated.

Doppler angle estimation using correlation

Conventional Doppler techniques can only detect the axial component of blood flow. To obtain the transverse flow component, an approach based on the dependence of Doppler bandwidth on Doppler angle has been widely investigated. To compute the bandwidth, a full Doppler spectrum is often required. Therefore, this approach has not been applied to real-time, two-dimensional Doppler imaging because of the long data acquisition time. To overcome this problem, a correlation-based method is proposed. Specifically, variance of the Doppler spectrum is used to approximate the square of the Doppler bandwidth. Because variance is computed efficiently and routinely in correlation-based color Doppler imaging systems, implementation of this method is straightforward. In addition, the two-dimensional velocity vector can be calculated and mapped to different colors using the color mapping function of current systems. Simulations were performed, and experimental data were also collected using a string phantom with the Doppler angle varying from 23 degrees to 82 degrees . Results indicate that the correlation-based method may produce significant errors if only a limited number of flow samples are available. With averaging, however, the Doppler angles estimated by the correlation-based method can achieve good agreement with the true angles by using only four flow samples with proper variance averaging.

Autostage sperm tracing system for semen evaluation

To overcome the limitation of the microscope field, the study proposed an autostage sperm tracing system (ASTS), which could trace a particular sperm for a long time and distance. The ASTS was constructed by assembling a commercial microscope, an image frame grabber, a personal computer, and a motorized stage. Its performance was tested by evaluating 6 semen samples and by comparing the evaluation with those of other semen evaluations. The ASTS broke through the limitation of the microscope field and traced a particular sperm as long as possible. It analyzed the sperm track and calculated the motility parameters, such as curvilinear velocity (Vcl), straight-line velocity (Vsl), and linearity (L(in)). The sperm quality was then evaluated in real time, and the user could decide to capture or abandon a particular sperm in the IVF The ASTS enables users to evaluate sperm progression for a long time and to have the global quality of a particular sperm in real time. Its open structure has the flexibility for micromanipulating a semen sample, and has the potential application associated with a modern IVF technique.

Effects of transmit focusing on finite amplitude distortion based second harmonic generation

Generation of the second harmonic signal was studied for finite amplitude distortion based harmonic imaging. Acoustic field amplitudes along the range axis of a fixed focus transducer were measured using a PVDF needle hydrophone. Results indicated that on-axis amplitudes strongly depended on the f-number at both the fundamental and the second harmonic frequencies. Differences of the on-axis amplitudes between the two frequencies were also investigated. To explore the possibility of increasing harmonic generation by extending the depth of focus, a two-focus transducer was employed. Hydrophone measurements, pulse-echo imaging and simulations were performed. Although the increase in harmonic generation depended on specific imaging parameters, the effectiveness of improving the harmonic signal-to-noise ratio (SNR) by increasing the depth of field was clearly demonstrated. Degradation in contrast resolution associated with the two-focus transducer was also evaluated. It was found that the contrast resolution was still significantly better than that of the fundamental image at the same frequency. Results of the study using the two-focus transducers can be generalized to imaging systems with full dynamic transmit focusing capabilities. In other words, it is expected that dynamic transmit focusing can improve the SNR of finite amplitude distortion based second harmonic imaging while improving the contrast resolution over fundamental imaging.

Strain measurements of rabbit Achilles tendons by ultrasound

Axial components of tendons' transverse strain fields were successfully measured in vitro by ultrasound. Achilles tendons of New Zealand white rabbits were used. Tendon inflammation was simulated by artificially inducing ischemia. Strain measurements were also correlated with conventional B-mode sonograms and histological micrographs. Results showed that strain measurements had reasonable agreement with histological examinations and provided better tissue differentiation than conventional B-mode imaging. For a given tendon, the strain values corresponding to different tissue layers were easily differentiated with an elastographic contrast-to-noise ratio ranging from 17 to 43 dB. Such differences, however, were not always present in the sonograms. Therefore, ultrasonic strain imaging may be a useful tool for assessing tendon disorders during the rehabilitation process.

Pulse compression for finite amplitude distortion based harmonic imaging using coded waveforms

Finite amplitude distortion based harmonic imaging has been used to reduce the image quality degradation produced by tissue inhomogeneities. Such harmonic signals are significantly lower than the linear components and are possibly too low compared to the dynamic range of the imaging system. To improve signal-to-noise ratio (SNR) without exceeding regulatory limits, coded excitation is explored. In addition, pulse compression schemes suitable for finite amplitude distortion based harmonic imaging are also developed. Note that due to the differences in harmonic generation, these compression schemes are different from those proposed for harmonic imaging using contrast agents. In this paper, simulation examples of SNR improvements by up to 8.2 dB are shown and the efficacy of the compression schemes is studied. Potential sources of performance degradation are also discussed.

Proposed CD4(+) T-cell criteria for staging human immunodeficiency virus-infected Chinese adults

The present treatment, prophylaxis, and prognostic staging of human immunodeficiency virus (HIV) disease rely heavily on peripheral CD4(+) T lymphocyte (CD4) changes. We correlated the clinical course of events and CD4 changes among consecutive HIV-infected ethnic Chinese adults in Hong Kong. Using death as end point, the estimated proportion survival and death incidences were used to compare CDC and proposed staging criteria based on stratified baseline CD4. A separate set of baseline CD4 per microliter (/microl) (percentage lymphocytes) stratification criteria of 1, >220/microl (>12%); 2, 100-220/microl (6-12%); and 3, <100/microl, (<6%) is proposed which can be used for staging HIV-infected Chinese adults. For our study population, our proposed criteria for stratifying baseline CD4 gave better discrimination and more predictive power than the CDC criteria. We assessed the potential impact of these new proposed criteria on anti-retroviral treatment and prophylaxis against opportunistic infections in our adult HIV-infected population.

Malignant fibrous histocytoma of the heart presenting as right ventricular outflow tract obstruction: a case report

Primary malignant fibrous histocytoma (MFH) of the heart is extremely rare. Herein, we report the case of a 17-year-old woman with a primary MFH in the right ventricular outflow tract, presenting with increasing dyspnea on exertion. Wide excision of the tumor, including part of the pulmonary artery and pulmonary valve, was performed under cardiopulmonary bypass. Her postoperative recovery was uneventful.

Transport, manipulation, and reaction of biological cells on-chip using electrokinetic effects

A microfluidic system was fabricated on a glass chip to study mobilization of biological cells on-chip. Electroosmotic and/or electrophoretic pumping were used to drive the cell transport within a network of capillary channels. Whole cells such as Saccharomyces cerevisiae, canine erythrocyte, and Escherichia coli were employed in this work. Photographs are presented to illustrate how cells are selected and transported from one location to another within the capillary network, with velocities up to about 0.5 mm/s in capillaries with a 15- x 55-microns cross section. The mixing of canine erythrocytes with the lysing agent sodium dodecyl sulfate, at an intersection within the chip, was performed to demonstrate that cell selection and subsequent reaction can be accomplished within the microchip.

Acute fulminant neuropathy in a patient with Churg-Strauss syndrome

We report a patient with an acute neuropathy initially mimicking Guillain-Barré syndrome, both clinically and electrophysiologically. Persistent eosinophilia, positive antineutrophil cytoplasmic antibody and eosinophilic vasculitis in sural nerve biopsy later confirmed Churg-Strauss syndrome. Since vasculitic neuropathy can present in an acute and fulminant form, the role of early antibody testing and sural nerve biopsy in atypical cases of acute neuropathy is emphasized.

Effects of Schisandrin B and alpha-tocopherol on lipid peroxidation, in vitro and in vivo

Effects of Schisandrin B (Sch B) and alpha-tocopherol (alpha-TOC) on ferric chloride (Fe3+) induced oxidation of erythrocyte membrane lipids in vitro and carbon tetrachloride (CCl4) induced lipid peroxidation in vivo were examined. While alpha-TOC could produce prooxidant and antioxidant effect on Fe(3+)-induced lipid peroxidation, Sch B only inhibited the peroxidation reaction. Pretreatment with alpha-TOC (3 mmol/kg/day x 3) did not protect against CCl4-induced lipid peroxidation and hepatocellular damage in mice, whereas Sch B pretreatment (0.3 mmol/3.0 mmol/kg/day x 3) produced a dose-dependent protective effect on the CCl4-induced hepatotoxicity. The ensemble of results suggests that the ability of Sch B to inhibit lipid peroxidation, while in the absence of pro-oxidant activity, may at least in part contribute to its hepatoprotective action.

Alterations in tissue glutathione antioxidant system in streptozotocin-induced diabetic rats

Changes in tissue glutathione antioxidant system in streptozotocin-induced diabetic rats for a period of 15 weeks were examined. Total glutathione level was significantly increased in kidney tissue, but were slightly decreased and increased in liver and heart tissues, respectively. The small changes in total glutathione level in the liver and heart, though not statistically significant, were associated with reciprocal alterations in the activity of gamma-glutamylcysteine synthetase (GCS). While the GCS activity was not changed in kidney tissue, the activity of gamma-glutathione peroxidase was significantly increased in kidney tissue. Insulin treatment could completely or partly normalize almost all of these changes induced by diabetes. However, the decrease in hepatic glutathione S-transferases activity in diabetic rats was not reversed by the insulin treatment. The ensemble of results suggests that the diabetes-induced alterations in tissue glutathione antioxidant system may possibly reflect an inter-organ antioxidant response to a generalized increase in tissue oxidative stress associated with diabetes.

Effect of a lignan-enriched extract of Schisandra chinensis on aflatoxin B1 and cadmium chloride-induced hepatotoxicity in rats

Treatment of rats with a lignan-enriched extract of the fruit of Schisandra chinensis could enhance hepatic antioxidant/detoxification system, as indicated by increases in hepatic reduced glutathione (GSH) level as well as hepatic glutathione reductase and glutathione S-transferase activities. The hepatoprotective action was evident after aflatoxin beta 1 or cadmium chloride (Cd) challenge. Schisandra chinensis pretreatment protected against aflatoxin B1-or Cd-induced hepatocellular damage in rats. However, pretreating rats with alpha-tocopherol acetate (vitamin E) did not protect against hepatic damage induced by both toxins. Results from the present as well as our previous studies demonstrate that the hepatoprotection afforded by Schisandra chinensis pretreatment is not hepatotoxin specific. Schisandra chinensis seems to be more effective than vitamin E in protecting against aflatoxin B1 and Cd toxicity. The mechanism of hepatoprotection afforded by Schisandra chinensis pretreatment may involve facilitation of both antioxidant and detoxification processes in the liver.

Schisandra chinensis-dependent myocardial protective action of sheng-mai-san in rats

Sheng-Mai-San (SMS), a traditional Chinese formulation used for the treatment of coronary heart disease, is comprised of Radix Ginseng, Fructus Schisandrae and Radix Ophiopogonis. Pretreatment with a lignan-enriched SMS (17 g/kg/day x 3, p.o.) was found effective in protection against isoproterenol-induced myocardial injury in rats, and in ischemia-reperfusion injury in isolated perfused hearts prepared from pretreated animals. Results obtained from pretreatment studies using extracts prepared by mixing various combinations of the three component herbs indicate that the major myocardial protective component in SMS is the lignan-enriched extract of Fructus Schisandrae.

Motor neuron disease in Hong Kong Chinese: epidemiology and clinical picture

This study documents the clinical features, incidence and prevalence of motor neuron disease (MND) in Hong Kong Chinese. Patients with MND who were alive between 1989 and 1992 were recruited by retrieval of medical records from the four major hospitals in Hong Kong, and by referral of neurologists, neurosurgeons and medical consultants. Mortality statistics was provided by the Census and Statistics Department. A total of 84 cases were identified with a male preponderance of 1.98:1. The average annual period incidence was 0.31/100,000 and the point prevalence on December 31, 1992, was 0.95/100,000. The mean age at onset was 55.5 years (range 19-81) with a peak observed from 55 to 65 years. The clinical features are similar to other reported series of MND. The incidence and mortality of MND in Hong Kong are therefore lower than the worldwide figures of 2.0/100,000 and 1.5/ 100,000, respectively.

Enhancement of hepatic glutathione regeneration capacity by a lignan-enriched extract of fructus schisandrae in rats

Exposure of liver homogenates to an in vitro tert-butyl hydroperoxide challenge can be used as a means for measuring the reduced glutathione regeneration capacity (GRC) of hepatic tissues. Pretreatment of rats with a lignan-enriched extract of Fructus Schisandrae (FS) caused a moderate enhancement of hepatic GRC in control rats, but the GRC enhancing effect of FS pretreatment on hepatic tissues was greatly exaggerated after CCl4 challenge. This in vitro bioassay can be used for investigating the hepatic GRC promoting action of orally active agents.

Retrospective dynamic transmit focusing

Dynamically-focused on receive, real-time array systems exhibit image degradation far from the focal zone of the fixed transmit lens. A retrospective filtering technique reducing the effects of the fixed transmitter is presented. The filter deconvolves the defocused transmit pattern producing a new in-focus transmit/receive image, where the filter coefficients are derived with a least-squares method. Experimental results are presented for a 128 channel array system showing the method's performance. A proposed architecture for real-time filtering is also discussed.

Profile of opportunistic infections among HIV-1 infected people in Hong Kong

BACKGROUND

To determine the spectrum of opportunistic infections in patients with human immunodeficiency virus (HIV-1) infection in Hong Kong.

METHODS

A retrospective study of 214 HIV-1-infected patients, seen between December 1984 and December 1993 in a specialist clinic for HIV/AIDS:

RESULTS

A majority (94%) of the patients in the cohort were male; 84% had acquired HIV via sexual contacts. Two-thirds were ethnic Chinese. Ninety-two (43%) had developed AIDS, and 54(25%) had presented with other non AIDS-defining opportunistic infections during the study period. The primary AIDS defining illnesses of 80 patients were infections: Pneumocystis carinii pneumonia (50%), extrapulmonary tuberculosis (10%) and cytomegalovirus (CMV) disease (8%). Opportunistic infections among Chinese and non-Chinese were similar in spectrum, though higher frequencies of infection with CMV, Mycobacterium avium intracellulare and tuberculosis were seen among Chinese, whereas the opposite was true for Pneumocystis carinii pneumonia, toxoplasmosis and cryptosporidiosis. Disseminated Penicillium marneffei infection was another significant disease for HIV-positive patients. Common non AIDS-defining opportunistic infections included herpes zoster, oral candidiasis, herpes simplex infection and genital/anal wart. The median CD4 count at HIV diagnosis for AIDS patients was much lower than non-AIDS patients (147 vs 546/ul). Survival of deceased AIDS patients was poor, with a median of only five months. Survival has however, apparently, improved over the recent years.

CONCLUSIONS

In Hong Kong, Pneumocystis carinii pneumonia remained the most common primary AIDS event, while Penicillium marneffei was emerging as another significant cause of major infection. Herpes zoster and oral candidiasis were the two most frequently encountered minor opportunistic infections.